11,695 research outputs found
Stripe, checkerboard, and liquid-crystal ordering from anisotropic p-orbital Fermi surfaces in optical lattices
We study instabilities of single-species fermionic atoms in the p-orbital
bands in two-dimensional optical lattices at noninteger filling against
interactions. Charge density wave and orbital density wave orders with stripe
or checkerboard patterns are found for attractive and repulsive interactions,
respectively. The superfluid phase, usually expected of attractively
interacting fermions, is strongly suppressed. We also use field theory to
analyze the possible phase-transitions from orbital stripe order to
liquid-crystal phases and obtain the phase diagram. The condition of
nearly-perfect Fermisurface nesting, which is key to the above results, is
shown robustly independent of fermion fillings in such p-orbital systems, and
the momentum of density wave oscillation is highly tunable.
Such remarkable features show the promise of making those exotic orbital
phases, which are of broad interest in condensed-matter physics, experimentally
realizable with optical lattice gases.Comment: final version, 8 pages, 5 figure
Potential Applications of functional Magnetic Resonance Imaging (fMRI) to Organizational Research: A Primer and Sample Study
The first purpose of this manuscript is to provide a primer for organizational researchers on both fMRI and brain physiology because few are likely to have encountered an in-depth treatment of either previously. The second purpose is to present the results of an actual fMRI study on an organizational topic (structured employment interviews) as a sample to help illustrate the potential of this type of research. Results of the sample study enhanced understanding of the brain processes behind responding to situational (SI) and behavior description (BDI) interviews, and offered several promising directions for follow-up research. To illustrate the latter, there appears to be separate region of the brain for handling complex social situations, which was activated only in the SI scans. This region could help explain the common use of the impression management tactic ingratiation in SIs. Given the emerging trend for larger universities to acquire fMRI equipment for research purposes, this type of research may be more viable then ever for organizational researchers
Half-metallic ferromagnetism and structural stability of zincblende phases of the transition-metal chalcogenides
An accurate density-functional method is used to study systematically
half-metallic ferromagnetism and stability of zincblende phases of
3d-transition-metal chalcogenides. The zincblende CrTe, CrSe, and VTe phases
are found to be excellent half-metallic ferromagnets with large half-metallic
gaps (up to 0.88 eV). They are mechanically stable and approximately 0.31-0.53
eV per formula unit higher in total energy than the corresponding
nickel-arsenide ground-state phases, and therefore would be grown epitaxially
in the form of films and layers thick enough for spintronic applications.Comment: 4 pages with 4 figures include
Spatial heterogeneity of piezoelectric properties in fatigued lead zirconate titanate ceramics
A spatial non-uniformity of the switching properties during the fatigue cycling in lead zirconate titanate ceramics was investigated by a quasi-static piezoelectric and a polarization switching measurements. The agreement between the local piezoelectric properties and the switching behavior of segmented samples was demonstrated. The observed spatial variation of the properties and its evolution with cycle number provides clear evidence of the presence of heterogeneous regions that possess a local fatigue state and the local switching behavior. These results can be explained as a result of the build-up of the spatially non-uniform field and the formation of frozen domains in the ceramics during cycling. The statistical analysis of spatial variation of the switching properties and its evolution with cycle number provides the evidence that the heterogeneity of the switching properties during the fatigue cycling in lead zirconate titanate ceramics is mostly related to the non-uniform change of the local characteristic switching time. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Structural study in Highly Compressed BiFeO3 Epitaxial Thin Films on YAlO3
We report a study on the thermodynamic stability and structure analysis of
the epitaxial BiFeO3 (BFO) thin films grown on YAlO3 (YAO) substrate. First we
observe a phase transition of MC-MA-T occurs in thin sample (<60 nm) with an
utter tetragonal-like phase (denoted as MII here) with a large c/a ratio
(~1.23). Specifically, MII phase transition process refers to the structural
evolution from a monoclinic MC structure at room temperature to a monoclinic MA
at higher temperature (150oC) and eventually to a presence of nearly tetragonal
structure above 275oC. This phase transition is further confirmed by the
piezoforce microscopy measurement, which shows the rotation of polarization
axis during the phase transition. A systematic study on structural evolution
with thickness to elucidate the impact of strain state is performed. We note
that the YAO substrate can serve as a felicitous base for growing T-like BFO
because this phase stably exists in very thick film. Thick BFO films grown on
YAO substrate exhibit a typical "morphotropic-phase-boundary"-like feature with
coexisting multiple phases (MII, MI, and R) and a periodic stripe-like
topography. A discrepancy of arrayed stripe morphology in different direction
on YAO substrate due to the anisotropic strain suggests a possibility to tune
the MPB-like region. Our study provides more insights to understand the strain
mediated phase co-existence in multiferroic BFO system.Comment: 18 pages, 6 figures, submitted to Journal of Applied Physic
EFFECT OF ANNUAL INFLUENZA VACCINATION ON MORTALITY AND HOSPITALIZATION IN PATIENTS WITH CHRONIC HEART DISEASE
Development and application of an indirect enzyme-linked immunosorbent assay using recombinant truncated Cap protein for the diagnosis of porcine circovirus-like virus P1
Suppression of Superconducting Critical Current Density by Small Flux Jumps in Thin Films
By doing magnetization measurements during magnetic field sweeps on thin
films of the new superconductor , it is found that in a low temperature
and low field region small flux jumps are taking place. This effect strongly
suppresses the central magnetization peak leading to reduced nominal
superconducting critical current density at low temperatures. A borderline for
this effect to occur is determined on the field-temperature (H-T) phase
diagram. It is suggested that the small size of the flux jumps in films is due
to the higher density of small defects and the relatively easy thermal
diffusion in thin films in comparison with bulk samples.Comment: 7 figures Phys. Rev. B accepted scheduled issue: 01 Feb 200
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